U.S. patent application number 12/237646 was filed with the patent office on 2010-03-25 for pressure relieving transition joint.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES, INC.. Invention is credited to Steven Ronald Fipke, William Shaun Renshaw.
Application Number | 20100071905 12/237646 |
Document ID | / |
Family ID | 41697926 |
Filed Date | 2010-03-25 |
United States Patent
Application |
20100071905 |
Kind Code |
A1 |
Renshaw; William Shaun ; et
al. |
March 25, 2010 |
Pressure Relieving Transition Joint
Abstract
A method of completing a wellbore having a branch wellbore
extending outwardly from a window in a parent wellbore is provided.
The method comprises positioning a tubular string in the window,
wherein the positioning comprises deflecting the tubular string
from the parent wellbore into the branch wellbore. The method also
comprises providing a particulate barrier outside and against the
tubular string proximate the window, the particulate barrier
substantially excluding transport of particulate matter from the
branch wellbore into the parent wellbore outside of the tubular
string through the window. The method also comprises the tubular
string passing fluid into the tubular string proximate the window
from a formation proximate to the window while substantially
excluding transport of particulate matter from the formation
proximate to the window into the tubular string.
Inventors: |
Renshaw; William Shaun;
(Edmonton, CA) ; Fipke; Steven Ronald; (Houston,
TX) |
Correspondence
Address: |
HALLIBURTON ENERGY SERVICES, INC.
5601 Granite Parkway, Suite 750
Plano
TX
75024
US
|
Assignee: |
HALLIBURTON ENERGY SERVICES,
INC.
Carrollton
TX
|
Family ID: |
41697926 |
Appl. No.: |
12/237646 |
Filed: |
September 25, 2008 |
Current U.S.
Class: |
166/313 ;
166/117.5; 277/314 |
Current CPC
Class: |
E21B 43/08 20130101;
E21B 41/0042 20130101; E21B 33/1208 20130101 |
Class at
Publication: |
166/313 ;
166/117.5; 277/314 |
International
Class: |
E21B 43/00 20060101
E21B043/00; E21B 23/03 20060101 E21B023/03; F16L 21/02 20060101
F16L021/02 |
Claims
1. A method of completing a wellbore having a branch wellbore
extending outwardly from a window in a parent wellbore, the method
comprising: positioning a tubular string in the window, wherein the
positioning comprises deflecting the tubular string from the parent
wellbore into the branch wellbore; providing a particulate barrier
outside and against the tubular string proximate the window, the
particulate barrier substantially excluding transport of
particulate matter from the branch wellbore into the parent
wellbore outside of the tubular string through the window; and the
tubular string passing fluid into the tubular string proximate the
window from a formation proximate to the window while substantially
excluding transport of particulate matter from the formation
proximate to the window into the tubular string.
2. The method of claim 1, wherein providing the particulate barrier
comprises swelling a sealing material adhered to the tubular
string, the swelling increasing a volume of the sealing material to
form a seal between the tubular string and the window, the swelling
activated by exposing the sealing material to at least one of
hydrocarbons and water.
3. The method of claim 2, wherein the tubular string comprises a
plurality of apertures and the sealing material comprises a
plurality of apertures, the fluid from the formation proximate to
the window passing into the tubular string through at least some of
the apertures in the swelling material and at least some of the
apertures in the tubular string.
4. The method of claim 3, wherein the dimension of the apertures in
the tubular string is effective to exclude transport of particulate
matter from the formation proximate to the window into the tubular
string.
5. The method of claim 3, wherein the tubular string further
comprises at least one screen proximate to the apertures in the
tubular string that excludes transport of particulate matter from
the formation into the tubular string.
6. The method of claim 2, wherein the seal between the tubular
string and the window blocks fluid from the formation proximate to
the window from passing around the outside of the tubular string
and into the parent wellbore.
7. The method of claim 1, wherein providing the particulate barrier
comprises one of injecting at least one of a gel and a foam between
the tubular string, the parent wellbore, and the branch wellbore
and packing of particulate matter into gaps between the tubular
string, the parent wellbore, and the branch wellbore resulting from
passing fluid from the formation proximate to the window into the
tubular string.
8. A completion tool for a well having a branch wellbore extending
outwardly from a window in a parent wellbore, comprising: a metal
pipe having an upper end and a lower end, a pipe wall opening, and
a plurality of apertures; and a particulate blocking member coupled
to the metal pipe, wherein after installation the upper end is
contained in the parent wellbore upwards from the window, the lower
end is contained in the branch wellbore, the pipe wall opening
couples the parent wellbore downwards from the window to the parent
wellbore upwards from the window, and the apertures relieve
pressure on the particulate blocking member from a formation
proximate to the window while blocking transport of particulate
matter from the formation proximate to the window into the metal
pipe and the particulate blocking member blocks transport of
particulate matter from the formation around the metal pipe into
the parent wellbore.
9. The completion tool of claim 8, wherein at least a middle
section of the metal pipe is slotted, wherein a plurality slots
comprise the plurality of apertures.
10. The completion tool of claim 9, wherein the slots are in the
range of about 0.01 inches wide to about 0.04 inches wide.
11. The completion tool of claim 8, wherein the particulate
blocking member is a swellable seal adhered to at least a middle
section of the metal pipe, the swellable seal to form a seal
between the metal pipe and the parent wellbore and the branch
wellbore when the completion tool is installed in a well, the
swellable seal having a plurality of apertures to promote relieving
pressure on the swellable seal from the formation proximate to the
window and the swellable seal having an opening aligned with the
pipe wall opening in the metal pipe.
12. The completion tool of claim 11, wherein the swellable seal
swells in volume when exposed to at least one of hydrocarbons and
water.
13. The completion tool of claim 8, wherein the plurality of
apertures in the metal pipe are each less than about 1 square
inches in area and a screen is attached to the metal pipe at the
location of the apertures to block transport of particulate
matter.
14. The completion tool of claim 13, wherein the plurality of
apertures in the metal pipe are arranged in pairs of apertures
about every three feet to about every five feet along the metal
pipe, wherein the pairs of apertures are offset from each other by
about 120 degrees, and wherein the apertures in the metal pipe are
offset about 120 degrees from the pipe wall opening in the metal
pipe.
15. The completion tool of claim 13, wherein the particulate
blocking member is a swellable seal adhered to at least a middle
section of the metal pipe, the swellable seal to form a seal
between the metal pipe and the parent wellbore and the branch
wellbore when the completion tool is installed in a well, the
swellable seal having a plurality of apertures to promote relieving
pressure on the swellable seal from the formation proximate to the
window, wherein at least one of the apertures in the swellable seal
is aligned with at least one of the apertures in the metal pipe,
wherein the apertures in the swellable seal are larger than the
apertures in the metal pipe, and wherein the swellable seal has an
opening aligned with the pipe wall opening in the metal pipe.
16. A transition joint seal for coupling a parent wellbore to a
branch wellbore extending outwardly from a window in the parent
wellbore, comprising: a metal pipe having a wall opening along a
first side of the metal pipe and a plurality of apertures along a
second side of the metal pipe; and a swell seal coupled to a middle
portion of the metal pipe, the swell seal being swellable in the
wellbore by increasing in a volume of the swell seal to promote
sealing between the window and the metal pipe and the swell seal
having a plurality of apertures, wherein at least one of the
apertures in the metal pipe align with at least one of the
apertures in the swell seal and the apertures in the metal pipe
substantially block transport of particulate matter from a
formation proximate to the window into the wellbore and allow fluid
flow from the formation proximate to the window into the
wellbore.
17. The transition joint of claim 16, wherein the swell seal is
adhered to the metal pipe.
18. The transition joint of claim 16, wherein the swell seal is
designed to swell when exposed to at least one of water and
hydrocarbons.
19. The transition joint of claim 18, wherein the swell seal is
comprised at least in part of a rubber material.
20. The transition joint of claim 16, wherein the transition joint
is about 40 feet long and wherein the length of the swell seal is
in the range of about 20 feet to about 30 feet.
21. The transition joint of claim 16, wherein the apertures in the
metal pipe substantially block fluid flow from the wellbore into
the formation proximate to the window.
22. The transition joint of claim 16, wherein a pressure relief
valve is installed in each of the apertures in the metal pipe,
wherein the pressure relief valves block transport of particulate
matter from the formation proximate to the window into the wellbore
and allows fluid flow from the formation proximate to the window
into the wellbore when a pressure differential between the
formation proximate to the window and the wellbore exceeds a
predefined threshold.
23. A transition joint seal for coupling a parent wellbore to a
branch wellbore extending outwardly from a window in the parent
wellbore, comprising: a screen structure having a wall opening
along a first side of the screen structure; and a swell seal
coupled to a middle portion of the screen structure, the swell seal
being swellable in the wellbore by increasing in a volume of the
swell seal to promote sealing between the window and the screen
structure and the swell seal having a plurality of apertures,
wherein the screen structure substantially blocks transport of
particulate matter from a formation proximate to the window into
the wellbore and allows fluid flow from the formation proximate to
the window through the apertures in the swell seal into the
wellbore.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] None.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
[0003] Not applicable.
BACKGROUND
[0004] Wells may comprise a plurality of wellbores. For example, a
main wellbore may be drilled and one or more branch wellbores may
be drilled off of the main wellbore. The branch wellbores may be
referred to in some contexts as lateral wellbores. Wells comprising
at least one lateral wellbore may be referred to in some contexts
as multilateral wells. A transition joint may be used in completion
of a multilateral well, for example to complete Technical Advance
Multilateral (TAML) level 3 completions, to provide a useful
transition between a parent wellbore and a branch wellbore bored
off of the parent wellbore. A parent wellbore may be the main
wellbore or may itself be a branch wellbore drilled off of the main
wellbore or off of another branch wellbore.
[0005] Sealing off a formation proximate to the junction of the
parent wellbore with the branch wellbore may be called for to avoid
formation particulate matter, for example fines and/or sand,
passing into the parent wellbore and/or the branch wellbore.
Particulate matter in the wellbores may plug or prematurely wear
production equipment and/or cause other problems. In some
circumstances, a pressure differential may exist between the
formation proximate to the junction of the parent wellbore with the
branch wellbore. The pressure differential may exert unwanted
stress on a seal of the transition joint.
SUMMARY
[0006] In an embodiment, a method of completing a wellbore having a
branch wellbore extending outwardly from a window in a parent
wellbore is disclosed. The method comprises positioning a tubular
string in the window, wherein the positioning comprises deflecting
the tubular string from the parent wellbore into the branch
wellbore. The method also comprises providing a particulate barrier
outside and against the tubular string proximate the window, the
particulate barrier substantially excluding transport of
particulate matter from the branch wellbore into the parent
wellbore outside of the tubular string through the window. The
method also comprises the tubular string passing fluid into the
tubular string proximate the window from a formation proximate to
the window while substantially excluding transport of particulate
matter from the formation proximate to the window into the tubular
string.
[0007] In another embodiment, a completion tool for a well having a
branch wellbore extending outwardly from a window in a parent
wellbore is disclosed. The completion tool comprises a metal pipe
having an upper end and a lower end, a pipe wall opening, and a
plurality of apertures. The completion tool also includes a
particulate blocking member coupled to the metal pipe. After
installation, the upper end is contained in the parent wellbore
upwards from the window and the lower end is contained in the
branch wellbore. After installation, the pipe wall opening couples
the parent wellbore downwards from the window to the parent
wellbore upwards from the window, and the apertures relieve
pressure on the particulate blocking member from a formation
proximate to the window while blocking transport of particulate
matter from the formation proximate to the window into the metal
pipe and the particulate blocking member blocks transport of
particulate matter from the formation around the metal pipe into
the parent wellbore.
[0008] In another embodiment, a transition joint seal for coupling
a parent wellbore to a branch wellbore extending outwardly from a
window in the parent wellbore is provided. The transition joint
seal comprises a metal pipe and a swell seal. The metal pipe has a
wall opening along a first side of the pipe. The swell seal is
coupled to a middle portion of the metal pipe and is swellable in
the wellbore by increasing in a volume of the swell seal to promote
sealing between the window and the metal pipe. A plurality of
apertures in the metal pipe align with a plurality of apertures in
the swell seal, and the apertures in the metal pipe substantially
block transport of particulate matter from a reservoir proximate to
the window into the wellbore and allow fluid flow from the
reservoir into the wellbore.
[0009] In another embodiment, a transition joint seal for coupling
a parent wellbore to a branch wellbore extending outwardly from a
window in the parent wellbore is disclosed. The transition joint
seal comprises a screen structure having a wall opening along a
first side of the screen structure and a swell seal. The swell seal
is coupled to a middle portion of the screen structure, the swell
seal being swellable in the wellbore by increasing in a volume of
the swell seal to promote sealing between the window and the screen
structure and the swell seal having a plurality of apertures. The
screen structure substantially blocks transport of particulate
matter from a formation proximate to the window into the wellbore
and allows fluid flow from the formation proximate to the window
through the apertures in the swell seal into the wellbore.
[0010] These and other features will be more clearly understood
from the following detailed description taken in conjunction with
the accompanying drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more complete understanding of the present disclosure,
reference is now made to the following brief description, taken in
connection with the accompanying drawings and detailed description,
wherein like reference numerals represent like parts.
[0012] FIG. 1 is an illustration of a well completion system
according to an embodiment of the disclosure.
[0013] FIG. 2 is an illustration of a well completion system with a
sealing material activated for sealing a transition zone between a
parent wellbore and a branch wellbore according to an embodiment of
the disclosure.
[0014] FIG. 3A is an illustration of a side view of a transition
joint in a first position according to an embodiment of the
disclosure.
[0015] FIG. 3B is an illustration of a side view of the transition
joint in a second position according to an embodiment of the
disclosure.
[0016] FIG. 3C is an illustration of a top view of the transition
joint according to an embodiment of the disclosure.
[0017] FIG. 3D is an illustration of a side view of the transition
joint according to an embodiment of the disclosure.
[0018] FIG. 4A is an illustration of a pressure relieving means
according to an embodiment of the disclosure.
[0019] FIG. 4B is an illustration of another pressure relieving
means according to an embodiment of the disclosure.
[0020] FIG. 5A is an illustration of a side view of a transition
joint in a first position showing an opening in a metal tubular
according to an embodiment of the disclosure.
[0021] FIG. 5B is an illustration of a side view of the transition
joint in a second position showing apertures in a metal tubular
according to an embodiment of the disclosure.
[0022] FIG. 5C is an illustration of a top view of the transition
joint showing an opening and apertures in a metal tubular according
to an embodiment of the disclosure.
[0023] FIG. 5D is an illustration of a side view of the transition
joint showing apertures in a metal tubular according to an
embodiment of the disclosure.
DETAILED DESCRIPTION
[0024] It should be understood at the outset that although
illustrative implementations of one or more embodiments are
illustrated below, the disclosed systems and methods may be
implemented using any number of techniques, whether currently known
or in existence. The disclosure should in no way be limited to the
illustrative implementations, drawings, and techniques illustrated
below, but may be modified within the scope of the appended claims
along with their full scope of equivalents.
[0025] A pressure relieving transition joint is disclosed that
achieves the desirable objective of blocking or reducing
propagation of particulate matter, such as fines and/or sand, into
a parent wellbore and/or a branch wellbore drilled off of the
parent wellbore while also avoiding collapse under stress from
pressure from a formation proximate to the junction of the branch
wellbore and the parent wellbore. In an embodiment, the pressure
relieving transition joint has one or more apertures facing the
formation that are operable to pass fluid such as liquids and/or
gases flowing from the formation into the wellbore while also
blocking or substantially reducing propagation of particulate
matter into the wellbore. The admission of fluids through the
apertures reduces the pressure from the formation on the transition
joint, thereby reducing the force on the transition joint from a
pressure differential between the outside and the inside of the
transition joint. In an embodiment, the contemplated pressure
relieving transition joint reduces a pressure differential between
the wellbore and the formation proximate to the junction of the
branch wellbore and the parent wellbore, immediately at the
junction.
[0026] A particulate barrier may be provided between the pressure
relieving transition joint, the parent wellbore, and the branch
wellbore that substantially excludes transport of particulate
matter, for example fines and/or sand, from the formation proximate
the junction of the parent wellbore and the branch wellbore around
the outside of the pressure relieving transition joint into the
pressure relieving transition joint. The particulate barrier may be
provided by a swelling seal. In an embodiment, the transition joint
comprises a swelling seal to form a seal between the transition
joint and a window drilled through the parent wellbore to drill the
branch wellbore. The swelling seal, which may also be referred to
in some contexts as a swellable seal, may exclude fluids as well as
particulate matter from flowing around the outside of the pressure
relieving transition joint into the pressure relieving transition
joint and/or into the parent wellbore. Apertures in a metal tubular
portion of the transition joint align with at least some of
apertures in the swelling seal in a portion of the transition joint
facing the window. The apertures permit fluid flow from the
formation proximate to the window to flow through the swelling seal
and the metal tubular, thereby reducing or eliminating a pressure
differential between the formation and the wellbore.
[0027] In another embodiment, the particulate barrier may be
provided by at least one of injection foam or injection gel that is
applied after 6r in coordination with positioning the pressure
relieving transition joint in the junction between the parent
wellbore and the branch wellbore. After being injected, the foam
and/or gel may set and provide a seal to block particulate matter
from entering the pressure relieving transition joint through gaps
between the pressure relieving transition joint and the junction of
the parent wellbore and the branch wellbore.
[0028] In an embodiment, the particulate barrier comprises packing
of particulate matter into gaps between the pressure relieving
transition joint, the parent wellbore, and the branch wellbore.
This packing of particulate matter may result, after the pressure
relieving transition joint is positioned in the junction between
the parent wellbore and the branch wellbore, from passing fluid
from the formation proximate to the junction into the wellbore.
This packing of particulate matter may continue to admit fluids
from the formation proximate to the junction to pass into the
wellbore while substantially blocking and/or excluding transport of
particulate matter into the pressure relieving transition
joint.
[0029] It is understood that in each case above the particulate
barrier acts substantially as a barrier or block to movement and/or
migration of particulate matter into the pressure relieving
transition joint from the formation proximate to the junction
between the parent wellbore and the branch wellbore and not
necessarily a barrier composed of particulates. In the last case,
however, the particulate barrier also happens to be composed of
particulates.
[0030] When installed in a wellbore, the pressure relieving
transition joint will pass hydrocarbons produced from production
zones in the parent wellbore and/or the branch wellbore below
and/or beyond the pressure relieving transition joint, through the
transition joint, and upwards into the wellbore above the
transition joint. Additionally, the pressure relieving transition
joint will provide access for downhole tools through the transition
joint to the parent wellbore and the branch wellbore below and/or
beyond the transition joint.
[0031] In an embodiment, the size of apertures in the metal tubular
portion may be effective to block or reduce propagation of
particulate matter into the wellbore. For example, in an
embodiment, the metal tubular is constructed of slotted tubing
wherein the slots are effectively sized to block or reduce
propagation of particulate matter into the wellbore. In an
embodiment, slotted tubing having slots with a width in the range
from about 0.01 inches to about 0.04 inches and a length in the
range from about 1.5 inches to about 3 inches may be employed, but
in other embodiments a different width and/or length slot may be
employed. In an embodiment, the size of the slots in the slotted
tubing may be selected based on the grain size distribution that is
expected at the location where the transition joint will be
installed in the wellbore. In another embodiment, a screen, such as
a sand screen, may be coupled to the metal tubular portion in
association with the apertures to block and/or reduce propagation
of particulate matter into the wellbore. In yet another embodiment,
pressure relief valves may be installed into the apertures in the
metal tubular portion to relieve any pressure differentials while
also blocking and/or reducing propagation of particulate matter
into the wellbore.
[0032] Turning now to FIG. 1, a well completion system 10 is
discussed. In the following description of the system 10 and other
apparatus and methods described herein, directional terms such as
"above," "below," "upper," and "lower," etc., are used for
convenience in referring to the accompanying drawings. "Above"
means relatively closer to the earth's surface along a wellbore,
and the term "below" means relatively farther from the earth's
surface. It is understood that the several embodiments of the
present disclosure may be utilized in various orientations, such as
inclined, inverted, horizontal, vertical, etc., and in various
configurations, without departing from the principles set forth
herein.
[0033] In FIG. 1, a main or parent wellbore 12 has been drilled and
then lined with casing 14. The parent wellbore 12 may extend
continuously to the earth's surface, or it may be a branch of
another wellbore. In another embodiment, however, the parent
wellbore 12 may be uncased and an open wellbore. If the parent
wellbore 12 is cased, the wellbore can be considered the interior
of the casing 14.
[0034] A branch wellbore 16 is drilled extending outwardly from a
window 18 formed through a sidewall of the casing 14. The window 18
can be formed before or after the casing 14 is installed in the
parent wellbore 12. For example, the window 18 could be formed by
anchoring a whipstock (not shown) in the casing 14, and then
deflecting a mill laterally off of the whipstock to cut the window
18 through the casing sidewall.
[0035] A formation or zone 20 surrounds the intersection and/or
junction between the parent and branch wellbores 12, 16. The
formation 20 may be said to be proximate to the junction between
the parent and branch wellbores 12, 16. In order to seal off the
formation 20 from the interior of the parent wellbore 12, while
also providing a useful transition between the parent and branch
wellbores 12, 16, an assembly 22 is positioned in the window 18.
The assembly 22 is depicted as including a tubular string 24 having
a transition joint 26 interconnected therein. In some contexts, the
assembly 22 may be referred to as a completion tool. In some
contexts, the tubular string 24 may be referred to as a metal
tubular having an upper end and a lower end.
[0036] During run in of the assembly 22, a lower end of the tubular
string 24 is deflected into branch wellbore 16, for example, by
using a whipstock or other deflector positioned in the parent
wellbore 12. After run in of the assembly 22, the lower end of the
tubular string 24 is contained in the branch wellbore 16 and an
upper end of the tubular string 24 is contained in the parent
wellbore 12. The lower end of the tubular string 24 may be cemented
in the branch wellbore 16, if desired.
[0037] The transition joint 26 has an opening 28 formed through a
sidewall thereof. In some contexts, the opening 28 may be referred
to as a pipe wall opening. The opening 28 may be formed in the
sidewall of the transition joint 26 before or after run in of the
assembly 22. The opening 28 provides fluid communication (and
preferably access) between an interior of the tubular string 24 and
the parent wellbore 12 external to the tubular string 24 below the
window 18. The opening 28, in some contexts, may be said to couple
the parent wellbore 12 downwards from the window 18 to the parent
wellbore 12 upwards from the window 18.
[0038] In an embodiment, a sealing material 30 may be provided on
the transition joint 26. In some contexts, the sealing material 30
may be referred to as a blocking member. The sealing material 30
may be provided in the form of a coating adhered externally to the
transition joint 26. However, other methods of attaching the
sealing material 30 to the transition joint 26 may be used. In an
embodiment, the sealing material 30 is not a coating but is a
continuous sleeve of sealing material 30 installed over the
assembly 22 at the transition joint 26 that adheres to the
transition joint 26 by friction. In some contexts, the sealing
material 30 may be referred to as a swellable seal. At least some
of the apertures in the sealing material 30 are aligned with at
least some of the apertures in the transition joint 26 and/or the
tubular string 24. An opening in the sealing material 30
substantially aligns with the opening 28 in the tubular string 24.
In an embodiment, it is not required that all of the apertures in
the sealing material 30 align with apertures in the transition
joint 26, and it is not required that all of the apertures in the
transition joint 26 align with apertures in the sealing material
30. In some embodiments, no sealing material 30 is applied to the
transition joint 26 until the transition joint 26 is installed in
the junction between the parent wellbore 12 and the branch wellbore
16 when a gel and/or foam is injected at the junction. The gel
and/or foam may set to form a seal between the transition joint 26
and the junction between the parent wellbore 12 and the branch
wellbore 16. In some contexts, the sealing material 30 may be said
to provide a particulate barrier outside and against the tubular
string 24 proximate the window 18.
[0039] The apertures unload pressure that may be present in the
formation 20 so that the pressure differential between the
formation 20 and the parent and branch wellbore 12, 16 is reduced
to a manageable magnitude, for example a magnitude that is
insufficient to breach the seal formed by the sealing material 30
when the assembly 22 is installed into the window 18. In an
embodiment, it is contemplated that the apertures unload pressure
to reduce the differential pressure to a magnitude of less than
about 50 pounds per square inch (PSI). In an embodiment, the
pressure gradient between the formation 20 and the parent and
branch wellbores 12, 16 may be directed substantially perpendicular
to the side of the transition joint 26 facing the formation 20
proximate to the window 18. Blocking means and/or devices are
provided for preventing propagation of particulate matter from the
formation 20 into the parent and branch wellbores 12, 16. The
blocking means may be provided by sand screens coupled to the
transition joint 26. The blocking means may be provided by
permeable filters coupled to the transition joint 26. The blocking
means may be provided by use of slotted pipe material in forming
the tubular string 24 and/or the transition joint 26, for example
slotted pipe having slots in the range of about 0.01 inches to
about 0.04 inches wide and in the range of about 1.5 inches to
about 3 inches long. The blocking means may be provided by pressure
relief valves installed in the apertures in the transition joint
26. The blocking means may be said to exclude or block transport of
particulate matter from the formation 20 into the wellbore.
[0040] The sealing material 30 swells when exposed to fluid in the
well. Preferably, the sealing material 30 increases in volume and
expands radially outward when a particular fluid or combination of
fluids contacts the sealing material 30 in the well. For example,
the sealing material 30 may swell in response to exposure to
hydrocarbon fluid (such as oil or gas) and/or in response to
exposure to water in the well. The sealing material 30 may be made,
at least in part, of a rubber compound. In other embodiments,
however, the sealing material 30 may be made of other
materials.
[0041] Referring now to FIG. 2, the system 10 is described after
the sealing material 30 has swollen in the window 18. Note that the
seal 32 is now formed by the swollen sealing material 30 between
the transition joint 26 and the window 18. This seal 32 may be
used, in part, to prevent particulate matter including fines, sand,
and other material from propagating from the formation 20 into the
parent wellbore 12, specifically preventing particulate matter from
passing between the sides of the transition joint 26 and the parent
and branch wellbores 12, 16 into the transition joint 26 and/or the
parent wellbore 12. The tubular string 24 could be cemented into
the branch wellbore 16 before or after the seal 32 is formed. In
addition, the sealing material 30, when swollen, may provide
another seal 34 between the transition joint 26 and the casing 14
in the parent wellbore 12. The seal 34 can be used as an annular
barrier above the opening 28. Note that the opening 28 is
conveniently positioned between the seals 32, 34 for providing
fluid communication between the interior of the tubular string 24
and the parent wellbore 12 below the window 18.
[0042] When the sealing material 30 has swollen in the window 18
and formed the seal 32 and optionally the seal 34, the apertures in
the sealing material 30 and in the transition joint 26 relieve
formation pressure that may be present in the formation 20. Without
the apertures, formation pressure may break one of the seal 32 and
the seal 34 and drive particulate matter under high pressure past
the seals 32, 34, eroding the sealing material 30 over time. The
relief of the formation pressure by the apertures reduces the
pressure differential between the formation 20 and the parent
wellbore 12 sufficiently to reduce stress on the seals 32, 34 to a
manageable level, for example to less than about 50 PSI.
[0043] Turning now to FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D, the
assembly 22 is discussed further. In FIG. 3A, a first side of the
assembly 22 is viewed. In FIG. 3B, a second side of the assembly 22
is viewed, where the second view is about opposite of the first
view. In FIG. 3C, a top view of the assembly 22 is shown. As best
seen in FIG. 3C, the opening 28 is located on an opposite side of
the sealing material 30 from a plurality of apertures 29 in the
sealing material 30. The opening 28 located in the tubular string
24 may be aligned with a corresponding opening in the sealing
material 30. In an embodiment, the apertures 29 in the sealing
material 30 are located in horizontal rows about 120 degrees apart
from each other in the horizontal direction. In an embodiment, the
apertures 29 are about 4 square inches in area. In another
embodiment, the apertures 29 may have a different size and area.
The size of the apertures 29 is designed to take into account the
swelling of the sealing material 30 when activated by at least one
of hydrocarbons and/or water in the wellbore, to avoid the
apertures 29 closing when the sealing material 30 swells. While
illustrated as roughly rectangular, the apertures 29 may take other
shapes. The apertures 29 may have straight shoulders or they may be
beveled or rounded.
[0044] In an embodiment, the assembly 22 may be about 40 feet long
and the sealing material 30 may be about 20 feet to about 30 feet
long. In an embodiment, the sealing material 30 is about 25 feet
long. In an embodiment, the rows of apertures 29 may be separated
in the range from about 3 feet to about 5 feet apart vertically. As
illustrated in FIG. 3D, in an embodiment, the apertures 29 may be
staggered with respect to each other.
[0045] In an embodiment, the tubular string 24 may be 75/8 inches
outside diameter and 61/8 inches inside diameter, but in other
embodiments the tubular string 24 may have a different outside
and/or inside diameter. In an embodiment, the sealing material 30
may have a pre-swelling outside diameter of 83/8 inches, but in
other embodiments the sealing material 30 may have a different
pre-swelling outside diameter. In one embodiment, when installed in
the window 18, the side of the assembly 22 illustrated in FIG. 3B
is oriented towards the window 18 and the formation 20 while the
side of the assembly 22 illustrated in FIG. 3A is oriented away
from the window 18 and the formation 20.
[0046] Turning now to FIG. 4A, a means for relieving differential
pressure between the formation 20 and an interior of the assembly
22 is described. In an embodiment, the tubular string 24 has a
plurality of apertures 31 aligned with the apertures 29 in the
sealing material 30. In an embodiment, the apertures 29 may each be
less than about 1 square inches in area. In an embodiment, the
apertures 29 may be circular and have a diameter of less than about
1 inch. In an embodiment, the apertures 29 may be circular and have
a diameter in the range of about 0.04 inches to about 0.3 inches.
The tubular string 24 may be coupled to a plurality of screens 33
to block or reduce the passage of particulate matter, for example
fines and/or sand, from the formation 20 into the wellbore. The
screens 33 may be retained within the apertures 29 by snap rings.
The apertures 29 may be at least partly threaded, and the screens
33 may screw into the threading in the apertures 29. The screens 33
may be welded to the tubular string 24 over the apertures 29. The
screens 33 may be adhered to the tubular string 24 using epoxy or
other adhesives. The screens 33 may be coupled to the tubular
string 24 using other means known to those skilled in the art. The
screens 33 may be aligned with the apertures 31. The screens 33 may
be attached to the outside of the tubular string 24 over the
apertures 31 or on the inside of the tubular string 24. In an
embodiment, the tubular string 24 or a portion of the tubular
string 24, for example the transition joint 26, may comprise a
screen structure.
[0047] When the assembly 22 is run in, the apertures 29, 31 and the
screens 33 allow fluid flow from the formation 20 to pass into the
assembly 22 and into the wellbore, thereby relieving a pressure
differential between the exterior and interior of the assembly 22,
while substantially blocking particulate matter. For example, sand
from the formation 20 may pack against the screens 33 but allow
fluid passage. In an embodiment, the screens 33 may allow fluid
flow from the formation 20 into the assembly 22 but block fluid
from the assembly 22 into the formation 20. In another embodiment,
the screens 33 may be replaced with permeable filters. In an
alternative, embodiment, the screens 33 may be replaced with
pressure relief valves (not shown) which open to allow fluid flow
to reduce a pressure differential between the formation 20 and the
interior of the assembly 22 while also blocking passage of
particulate matter into the wellbore and closing to block fluid
flow from the interior of the assembly to the formation 20.
[0048] Turning now to FIG. 4B, another means for relieving
differential pressure between the formation 20 and an interior of
the assembly 22 is described. In an embodiment, the tubular string
24 is at least partially constructed of slotted tubing. For
example, the tubular string 24 may be constructed of tubing having
slots in the range of about 0.01 inches to about 0.04 inches wide
and in the range about 1.5 inches to about three inches long. In
another embodiment, other slot sizes may be employed that are
effective to block and/or exclude transport of particulate matter
from the formation 20 into the wellbore. The apertures 31 in the
tubular string 24 may be provided by the slots. The apertures 31
may allow fluid flow from the formation 20 into the interior of the
assembly 22, thereby relieving and reducing a pressure differential
between the formation 20 and the wellbore, while blocking the entry
of particulate matter, for example fines and/or sand, from the
formation into the wellbore. For example, sand from the formation
20 may pack against the apertures 31 in the tubular string 24
provided by the slots but allow fluid passage through the slots
into the wellbore.
[0049] In an embodiment, the tubular string 24 may not have the
sealing material 30. In this embodiment, the lower end of the
tubular string 24 is deflected into the branch wellbore 16, and
fluid flows from the formation 20 into the wellbore through the
apertures 31 in the tubular string 24 and around the junction of
the window 18 with the assembly 22. Sand packs against the screens
33 and/or apertures 31 and in the junction of the window 18 with
the assembly 22. While initially some sand and/or particulate
matter may propagate through the junction of the window 18 with the
assembly 22, as the particulate matter packs the junction further
propagation of sand and/or particulate matter stops.
[0050] Turning now to FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D the
spatial relationship between the opening 28 in the tubular string
24 and the apertures 31 in the tubular string 24 are discussed. The
apertures 31 may be disposed in horizontal rows, apertures 31 in
the same row horizontally offset from each other by about 120
degrees. The apertures 31 may be on a side of the tubular string 24
about opposite of the side of the tubular string containing the
opening 28. In an embodiment, the horizontal row of apertures 31
may be located in the range of about every three feet to about five
feet vertically along the tubular string 24. As illustrated in FIG.
5D, the apertures 31 may be staggered and/or offset from each
other.
[0051] While several embodiments have been provided in the present
disclosure, it should be understood that the disclosed systems and
methods may be embodied in many other specific forms without
departing from the spirit or scope of the present disclosure. The
present examples are to be considered as illustrative and not
restrictive, and the intention is not to be limited to the details
given herein. For example, the various elements or components may
be combined or integrated in another system or certain features may
be omitted or not implemented.
[0052] Also, techniques, systems, subsystems, and methods described
and illustrated in the various embodiments as discrete or separate
may be combined or integrated with other systems, modules,
techniques, or methods without departing from the scope of the
present disclosure. Other items shown or discussed as directly
coupled or communicating with each other may be indirectly coupled
or communicating through some interface, device, or intermediate
component, whether electrically, mechanically, or otherwise. Other
examples of changes, substitutions, and alterations are
ascertainable by one skilled in the art and could be made without
departing from the spirit and scope disclosed herein.
* * * * *